Manufacturing expands slowly in January

WASHINGTON — U.S. manufacturing barely expanded last month as cold weather delayed shipments of raw materials and caused some factories to shut down.

The Institute for Supply Management, a trade group of purchasing managers, said Monday that its index of manufacturing activity fell to 51.3 in January from 56.5 in December. It was the lowest reading since May, though any reading above 50 signals growth. Manufacturers said export orders grew at a healthy pace but slightly less than in the previous month.

The figures suggest that U.S. manufacturing is slowing after a strong finish to last year. Auto sales have decelerated, and businesses are spending cautiously on machinery and other large factory goods. The slowdown means that economic growth in the first three months of this year may be less than the strong 3.6 percent annual pace in the second half of 2013.